TOXOPLASMA GONDII INFECTION IN LLAMA (LLAMA GLAMA): ACUTE VISCERAL DISSEMINATED LESIONS, DIAGNOSIS, AND DEVELOPMENT OF TISSUE CYSTS

摘要

Clinical toxoplasmosis has been reported in many species of warm-blooded animals but is rare in camelids. Here we report acute fatal systemic toxoplasmosis involving heart, thyroid gland, stomach, intestine, diaphragm, kidneys, adrenal glands, and liver of a 13-mo-old llama (Llama glama). Many Toxoplasma gondii tachyzoites were associated with tissue necrosis in multiple organs. Death was attributed to severe myocarditis. Ulcers associated with numerous tachyzoites were present in the C3 compartment of the stomach. Tissue cyst development was followed using bradyzoite-specific T. gondii antibodies. Individual intracellular, and groups of 2 or more, bradyzoites were identified in hepatocytes, biliary epithelium, myocardiocytes, lung, diaphragm, thyroid gland, spleen, and stomach. Lesions in the brain were a few microglial nodules and very early tissue cysts containing 1-3 bradyzoites. These observations suggest that the animal had acquired toxoplasmosis recently. Diagnosis was confirmed immunohistochemically by reaction with T. gondii-specific polyclonal rabbit serum but not with antibodies to the related protozoan Neospora caninum. Genetic typing using the DNA extracted from paraffin-embedded myocardium of llama and 10 PCR-restriction fragment length polymorphism (RFLP) markers revealed a type II allele at the SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, PK1 L358, and Apico loci; therefore, this isolate belongs to the ToxoDB PCR-RFLP genotype #1, which is most common in North America and Europe.